adulterer (n.)

c. 1500, "act of adulterating; state of being debased by mixture with something else," generally of inferior quality, from Latin adulterationem (nominative adulteratio) "an adulteration, sophistication," noun of action from past-participle stem of adulterare "corrupt, falsify; debauch; commit adultery," from ad "to" (see ad-) + alterare "to alter" (see alter), though Watkins explains it as ad alterum "(approaching) another (unlawfully)." Meaning "a result of adulterating" is from 1650s.

also adultress, "woman guilty of adultery," an early 17c. substitution for earlier avoutresse (late 14c.), agent noun in fem. form from obsolete verb adulter "commit adultery" (see adulterer), with fem. ending -ess.

"pertaining to or given to adultery; illicit," c. 1600, a classical correction (replacing earlier avoutrious "addicted to adultery," c. 1400), from obsolete verb adulter (see adulterer) + -ous. Related: Adulterously. Adulterine (1640s, from Latin adulterinus) was used in the sense "pertaining to adultery, born of adultery."